The train driver in the Spanish derailment disaster has been released after being charged with the 79 deaths in the country's worst train accident in decades.

Francisco Jose Garzon Amo faces multiple counts of negligent homicide after being questioned in a two-hour hearing with the judge. The investigation has increasingly focused on why he failed to brake in time to stop the train from hurtling into a dangerous curve, where it careered off the tracks and slammed into a concrete wall.

Judge Luis Alaez ruled that Garzon was not a flight risk and released him without bail, but ordered him to appear before the court once a week and not to leave Spain.

Several Spanish neswspapers, including leading daily El Pais, reported that the driver acknowledged to the judge that the train was travelling too fast, but that he briefly stopped paying attention. The Spanish rail agency has said the brakes should have been applied 2.5 miles before the train hit the curve

One witness said that minutes after the crash Garzon told him he could not brake.

Evaristo Iglesias, said he and another person accompanied the blood-soaked Garzon to flat ground where other injured people were being laid out, waiting for emergency services to arrive. "He told us that he wanted to die," Mr Iglesias told Antena 3 television. "He said he had needed to brake but couldn't." He added that Garzon said "he had been going fast."

Spain's state-run train company has described him as an experienced driver who knew the route well. Officials said 70 people injured in the train accident remained hospitalised, 22 of them in critical condition.

The crash left a pall over the city of Santiago de Compostela, an important Catholic religious site that had been preparing for a feast celebrating Spain's patron saint. Shrines and regional flags with black mourning ribbons have dotted the area since Wednesday's crash.

Crown heir Prince Felipe, his sister Princess Elena and Prime Minister Mariano Rajoy were among those scheduled to attend a memorial mass in the ancient cathedral in Santiago de Compostela.

Many families of victims were also expected to attend the mass, which is to be televised nationally. The ceremony is open to the public and a giant screen is to be set up in one of the squares outside the cathedral, where thousands of pilgrims traditionally gather on arriving in the city.